How are the following conversions carried out?
$(i)$ Propene $\rightarrow$ Propan$-2-$ol.
$(ii)$ Benzyl chloride $\rightarrow$ Benzyl alcohol.
$(iii)$ Ethyl magnesium chloride $\rightarrow$ Propan$-1-$ol.
$(iv)$ Methyl magnesium bromide $\rightarrow$ $2-$Methylpropan$-2-$ol.

(N/A) $(i)$ Acid-catalyzed hydration of propene follows Markovnikov's rule to yield propan$-2-$ol.
$CH_3-CH=CH_2 + H_2O \xrightarrow{H^+} CH_3-CH(OH)-CH_3$
$(ii)$ Benzyl chloride reacts with aqueous $NaOH$ via nucleophilic substitution to form benzyl alcohol.
$C_6H_5CH_2Cl + NaOH(aq) \to C_6H_5CH_2OH + NaCl$
$(iii)$ Ethyl magnesium chloride reacts with methanal $(HCHO)$ to form an adduct,which upon hydrolysis yields propan$-1-$ol.
$C_2H_5MgCl + HCHO \to C_2H_5CH_2OMgCl \xrightarrow{H_2O/H^+} C_2H_5CH_2OH + Mg(OH)Cl$
$(iv)$ Methyl magnesium bromide reacts with acetone $(CH_3COCH_3)$ to form an adduct,which upon hydrolysis yields $2-$methylpropan$-2-$ol.
$CH_3MgBr + CH_3COCH_3 \to (CH_3)_3COMgBr \xrightarrow{H_2O/H^+} (CH_3)_3COH + Mg(OH)Br$